Technical Field
The present disclosure relates to a plug connector with integrated galvanic separation. The disclosure also relates to a shielding element which may be used in such plug connector and/or in other plug connectors.
Description of the Related Art
In the field of industrial plug connectors, and specifically in the field of round plug connectors such as the M12 series, Ethernet protocols are being used to an increasing extent, for example in the field of industrial Ethernet switches.
In order to protect the transceiver and to ensure a desired signal quality, the IEEE 802.3 standard, for example, specifies galvanic separation of the PHY side (the Physical Layer; i.e., the transceiver side) from the MDI side (Medium Device Interface; i.e., the plug connector and CAT cable), said separation generally being realized by a transformer.
Such transformers have conventionally been provided between the actual chip and the respective plug connector, i.e., they were interposed as separate components.
In the field of RJ plugs (RJ45 plugs, in particular) “MagJacks”, for example, in which the transformer is integrated in the plug socket, are known. The contacts inside the RJ socket are arranged on the inner surface surrounding an inserted plug. The transformers, and more particularly a printed circuit board on which the transformers are mounted, are arranged along a portion of such an inner surface, typically parallel to and offset from a plane defined by the contact surfaces.
Such an approach is not transferable to other plug connection concepts in which the contacts are on the inside, i.e., are enclosed by the counterpart of the plug connector when contact is made.
Furthermore, RJ45 plugs are not considered reliable enough for numerous industrial plug applications, due to their particular construction.
In the field of M12 plug connectors, for example, the transformers are still provided as separate components at present. Providing such separate components increases the amount of construction space that is required. Additionally, the layout of a circuit board, on which the plug connector is to be mounted, becomes more complex in view of the need for sufficient air gaps and leakage clearances. Another factor is that the conductors which are then needed can produce additional crosstalk on the transceiver chip, which is generally sensitive. Besides the additional work involved in placing the components on the circuit board, the additional wiring involved also has negative impacts on the transmission characteristics (signal integrity).
There is therefore a desire for a plug connector concept which can ensure the galvanic separation between the PHY and the MDI side as required by IEEE 802.3, for example, and with which the aforementioned disadvantages, i.e., additionally required construction space, a need for sufficient air gaps and leakage clearances, additional crosstalk on the transceiver chip, extra work involved for installation and deterioration in transmission characteristics, can be avoided, or at least reduced in comparison with conventional separate design.
In the context of industrial plug connectors, there is furthermore a desire for an electrical contacting in a shielding manner between the plug connector (or parts thereof) and a housing. Example of means for such shielding connection are described in DE 10 2012 105 256 A1 and WO 2012/041310 A1.
DE 10 2012 105 256 A1 discloses an insulation body for a plug connector which is provided with a shielding spring having a shape similar to that of a clover leaf, which is provided inside a partially circumferential slot in the insulation body, electrically contacting a shielding cross inside the insulation body. The shielding spring extends laterally to the outside of the insulation body and thus allows for a conductive contact with a housing for the plug connector.
WO 2012/041310 A1 discloses plug connector having an insulation body provided with a circumferential groove, in which a shielding spring is provided in the form of a helical spring, so to allow for a conductive connection between a shielding cross of the plug connector and a (grounded) front plate insert.
A difficulty involved with such shielding springs is that-under given circumstances-there might be a need for a relative strong force to be exerted upon assembling the plug connector with the housing, involving the risk of damaging a circuit board to which the plug connector is attached.
In the case of DE 10 2012 105 256 A1, it may happen that the shielding spring is offset inside the slot such that it blocks the passage of the plug connector into the housing or housing sleeve. With regard to WO 2012/041310 A1, there is furthermore a possibility that the helical shielding spring is moved out of its groove during the insertion of the plug connector into the front plate insert, while the moving may severe the electrical connection between the shielding spring and the shielding cross.
Also known are arrangements where there is provided on a ledge a connection element in the form of a curved disc spring or a wave washer, which is then compressed upon insertion of the plug into the sleeve so to provide for a conductive connection. A similar arrangement provides for only a partially surrounding connection element (e.g., having a form similar to a C), wherein the arms of the connection element extend obliquely so to being bend upon connection.
A disadvantage of such arrangements is that the reliability of the connection depends on the accuracy of the positioning of the plug connector in the circuit board in the direction of compression of the connection element, as possibly to compression of the connection element might be insufficient for a good connection.
There is thus also a desire for a shielding element for a plug connector allowing for a reliable electrical connection basically irrespective of the positional accuracy of the placement of the plug connector, while reducing a risk of damage in view of the forces needed for providing the electrical connection.